Mutations in Exons 8 and 11 of c-kit Gene in Canine Subcutaneous Mast Cell Tumors and Their Association with Cell Proliferation

The prognostic significance of internal tandem duplication (ITD) mutations in exons 8 and 11 of c-kit has been well-described for canine cutaneous mast cell tumors (MCTs), but c-kit mutations have rarely been reported in subcutaneous MCTs. The objective of this study was to identify the prevalence of ITD mutations in exons 8 and 11 of c-kit in canine subcutaneous MCTs and to investigate its association with histologic grade, KIT pattern, and proliferation markers. ITD mutations in exons 8 and 11 of c-kit, mitotic count, Ki67 index, AgNOR number, Ki67xAgNOR score, KIT pattern, and histologic grade (two-tier system) were retrospectively recorded for 216 dogs with subcutaneous MCTs. ITD mutations in exons 8 and 11 of c-kit were detected in 23 (10.6%) and 12 (5.56%) subcutaneous MCTs, respectively. Exon 11 mutations were significantly associated with Kiupel high grade (p < 0.001) and increased mitotic count (p < 0.001) compared to subcutaneous MCTs with no mutations in exons 8 or 11 (p = 0.002) or subcutaneous MCTs with a mutation in exon 8 (p = 0.001). There was no significant association of either c-kit mutation with KIT patterns or proliferation activity. This study identified a higher prevalence of ITD mutations in exons 8 and 11 of c-kit in subcutaneous MCTs than previously reported. Like their cutaneous counterpart, subcutaneous MCTs with exon 11 mutations were more likely to be histologically high grade and have a higher mitotic count, whereas such associations were not observed in subcutaneous MCTs with exon 8 mutations

PID 2129 Recuperación del pastizal natural degradado en un monte nativo sometido a desarbustado mecánico

El objetivo general del proyecto fue evaluar la respuesta del pastizal natural al desarbustado mecánico, en un monte nativo en pastoreo con diferentes grados de enmalezamiento. En un establecimiento agropecuario mixto de Villaguay (Entre Ríos), se determinaron dos niveles de enmalezamiento con especies arbustivas (más del 30% y menos del 30% de cobertura) y en cada situación se estudió el efecto del desarbustado mecánico. Para monitorear la evolución del pastizal ,se midió la cobertura y biomasa del estrato herbáceo y arbustivo, en el período junio/08-agosto/10. Se realizó además toma de muestras de suelo en la situación inicial y final del ensayo (nov/10) para analizar el banco de semillas. Hacia noviembre/09, en las áreas desarbustadas se evidenció una tendencia favorable en la composición del pastizal, registrándose una importante reducción de especies arbustivas.  En áreas sin desarbustar (tanto en las de alta como en las de baja cobertura de arbustivas), si bien las especies forrajeras incrementaron su abundancia-cobertura, las no forrajeras (en especial Baccharis punctulata y Melica macra) mantuvieron valores similares a los iniciales. En el muestreo de marzo/10, se observó  una importante reinfestación con especies arbustivas en el lote en general, resultando mayor en los sectores con alto enmalezamiento inicial. El desarbustado mecánico evidenció una mayor eficiencia al aplicarse en áreas con bajo enmalezamiento inicial, donde B. punctulata representaba una mayor contribución porcentual  a la cobertura total de especies arbustivas. El impacto de este tipo de prácticas sobre el control de la chilca favoreció el desarrollo de M. macra, especie que incrementó significativamente su cobertura hacia finales del estudio, por lo que para el control de espartillo sería necesario recurrir a una práctica complementaria. De los resultados de este trabajo se deduce que un único desarbustado mecánico resulta insuficiente para el control de B. punctulata y M. macra, requiriéndose la aplicación de un ciclo de desarbustados cuya frecuencia dependerá de cada caso en particular.  Se observó una diferencia sustancial entre la composición de especies del banco de semillas y la vegetación establecida en el pastizal en estudio. A inicios del ensayo, en las áreas con baja cobertura de arbustivas, se determinó una densidad total media de 4093 semillas/m2 en el banco y una riqueza de 24 especies, siendo dominantes Salvia sp. (38,8%) y Polygonum convolvulus (27%). En el muestreo final, la densidad total fue de 6769 semillas/m2, con una riqueza específica de 9 especies, siendo las  dominantes una leguminosa (36%) y Stellaria media (32%).  En las áreas con alta cobertura inicial de arbustivas, la densidad total a inicios del ensayo fue de 2853 semillas/m2, mientras que la riqueza fue de 13 especies.  Una especie aún no identificada fue la que aportó la mayor densidad de semillas al banco (27,6%), seguida por Polygonum sp (15,4%) y Salvia sp. (10,4%). Al final del estudio se registró una densidad de 11076 semillas/m2. Paspalum sp. y Salvia sp. resultaron las especies de mayor aporte al banco (23% y 15%, respectivamente)

Case report: Sublingual mucinosis in a dog

Oral focal mucinosis (OFM) is a rare clinic-pathological condition histologically similar to focal skin mucinosis and thus, OFM is considered as the oral counterpart of cutaneous focal mucinosis (1, 2). Cutaneous mucinosis refers to an excessive deposition of mucinous substance in the dermis that clinically manifests as a thickening of the skin or as a vesicular appearance (3, 4). A generalized cutaneous mucinosis, of likely genetic origin, occurs primarily in Shar-pei dogs, giving them its characteristic appearance (5). In other breeds, severe mucinosis is associated with secondary diseases such as intertrigo, bacterial infections and entropion, all of which can lead to severe deterioration in the health of the animal (6). In human, OFM was first described and named by Tomich in 1974 (1). Its pathogenesis is still unclear, but an increased production of hyaluronic acid (HA) by fibroblasts in expense of collagen production and myxoid degeneration is suggested (7, 8). Clinically, oral lesions often present as a small (<1 cm) submucosal, single, pink, and slow-growing asymptomatic nodule containing gelatinous material (8, 9). The gingiva and palate are the most affected sites (9, 10). OFM has already been reported in literature in a dog as a nodular lesion on the buccal mucosa (11). This is the first case described with this type of presentation

Nuevos Gastrópodos (Eotomariidae y Subulitidae) en las localidades de Piedra Shotel y Cerro La Trampa, Formación Río Genoa, Pérmico inferior del Chubut

Varios autores (Sabattini, 1975, 1978, 1984, 1992, 1995 a-b, 1997; Sabattini y Noirat, 1969; Pagani y Sabattini, 2002; y Cúneo y Sabattini, 1987) han contribuido al conocimiento sistemático y bioestratigráfico de la fauna de gastrópodos neopaleozoicos en diferentes unidades de la Cuenca Tepuel-Genoa (figura 1). Sin embargo, debido al deficiente muestreo de los niveles marinos en el área de la Formación Río Genoa, se hacía necesario un trabajo más detallado a fin de poder recabar información sobre los grupos de invertebrados presentes en dichos niveles cuyo único antecedente corresponde a Pagani y Cúneo (2003). El presente trabajo tiene como finalidad ampliar el conocimiento sistemático de gastrópodos neopaleozoicos de la Formación Río Genoa, principalmente en las localidades de Piedra Shotel y Cerro La Trampa (figura 1). Se da a conocer la presencia de una nueva especie de Mourlonia de Koninck (1883), Mourlonia cuneoi nov. sp, y se obtiene el registro de Peruvispira sueroi Sabattini y Noirat (1969) en la localidad de Piedra Shotel, hecho que permite, debido al buen estado de preservación de los ejemplares, enmendar la diagnosis de la especie. Del análisis de la distribución geográfica de la fauna, y siguiendo los esquemas propuestos por Pagani y Sabattini (2002) se considera que la edad de la misma es pérmica temprana.Fil: Ferrari, Silvia Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Sabattini, Nora Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentin

Incorporation of Biologic Variables Into the Staging for Canine Cutaneous and Subcutaneous Mast Cell Tumours: Proposal of the UBo pTNM System

Canine cutaneous mast cell tumours (MCTs) are currently staged based on the World Health Organization (WHO) classification, which has remained unchanged since its initial formulation. Our study aimed to assess the reliability of a novel pTNM staging system, which incorporates tumour extent (T), lymph node involvement (N), presence of distant metastases (M) and the two-tier histologic grade. We analysed medical records of dogs with one or more cutaneous/subcutaneous completely staged MCT, undergoing tumour excision with lymphadenectomy, unless distant metastases were present, in which cases, medical therapy was administered. Dogs were categorized into three stages: I (T1-2N0M0), II (T1-2N1M0) and III (distant metastases). Stages I and II were further divided based on histologic grade into 'low' and 'high'. Substage b was defined as the presence of tumour diameter of ≥3 cm and/or ulceration. Of 226 dogs, 87 (38.5%) were in Stage I (I-low, n = 75; I-high, n = 12), 107 (47.3%) in Stage II (II-low, n = 59; II-high, n = 48), and 32 (14.2%) in Stage III. The newly proposed staging system was able to significantly stratify the population for both time to progression and tumour-specific survival. Compared to Stage I-low, the risk of progression increased significantly for Stage I-high (18.3 times), Stage II-low (8.5 times), Stage II-high (41.5 times) and Stage III (110.3 times). The staging system was highly prognostic for both cutaneous and subcutaneous MCTs. Prospective validation studies are essential to compare this new system with the current WHO staging and further validate its accuracy and clinical utility

A Retrospective Clinico-Pathologic Study of 35 Dogs with Urethral Transitional Cell Carcinoma Undergoing Treatment

: Chemotherapy and cyclooxygenase inhibitors (COXi) are primary treatments for canine urethral transitional cell carcinoma (uTCC), a tumor known for its aggressiveness and poor prognosis. This retrospective study aimed to evaluate the clinico-pathological characteristics, treatment modalities, and prognostic factors of 35 dogs with confirmed uTCC that received chemotherapy and COXi. Upon admission, urethral obstruction (UO) and urinary tract infection (UTI) were observed in seven (20%) dogs each. Gemcitabine (n = 20; 57.1%) and vinblastine (n = 10; 28.6%) were commonly used as first-line therapies, with four dogs also receiving radiation therapy. Based on RECIST, one (2.9%) dog achieved complete remission, nine (25.7%) partial remission, 20 (57.14%) showed stable disease, and five (14.3%) progressed. Among dogs with UO, six (85.7%) showed resolution or improvement after the first chemotherapy dose. The median time to local progression was 171 days (range: 107-235), and the median survival time was 333 days (range: 158-508). Dogs with UO upon admission had a higher risk of local progression, while both UO and UTI were associated with an increased risk of overall disease progression and tumor-related death. Additionally, gemcitabine significantly improved metastatic control. This study identified UO and UTI as negative prognostic factors, highlighting the importance of a multimodal approach in managing uTCC

The 2-tier grading system identifies canine cutaneous and/or subcutaneous mast cell tumors with aggressive biological behavior regardless of growth model

Histologic grading of canine cutaneous mast cell tumors (cMCTs) has prognostic and therapeutic implications, yet validation for subcutaneous MCTs (scMCTs) is lacking. For scMCTs with or without dermal invasion, determining their biological behavior remains poorly standardized and sometimes sparks controversy. This prospective study aimed to assess the prognostic utility of the 2-tier histologic grading system in MCTs with different growth models (GMs) and explore the prognostic impact of the GM itself. We assessed 6 histologic GM categories: solely cMCT (C-SC0), cMCT with superficial (C-SC1) or deep subcutaneous (C-SC2) involvement, solely scMCT (SC-C0), and scMCT with deep (SC-C1) or superficial (SC-C2) infiltration of the dermis. Ninety-one MCTs from 76 dogs undergoing excision and regional/sentinel lymphadenectomy were examined. GM classification identified 11 (12%) C-SC0 tumors, 12 (13%) C-SC1, 15 (16%) C-SC2, 21 (23%) SC-C0, 15 (16%) SC-C1, and 17 (19%) SC-C2. Mitotic count, 2-tier grade, nodal involvement, surgical margins, and outcome were stratified according to GM. scMCTs lacking dermal invasion, historically associated with a benign clinical course, had a poor prognosis in 10% of cases. cMCTs exhibiting deep subcutaneous involvement included the largest percentage of high-grade tumors (33%), had the highest occurrence of overt nodal metastases (33%), and had the lowest 1-year survival rate (86%). Histologic grade was confirmed as a relevant prognostic factor, surpassing nodal involvement and histologic margin status. The 2-tier histologic grading enabled the identification of all MCTs with aggressive biological behavior, regardless of their cutaneous or subcutaneous location

Prevalence of p53 dysregulations in feline oral squamous cell carcinoma and non-neoplastic oral mucosa

Squamous cell carcinoma is the most common malignant oral tumor in cats. The late presentation is one of the factors contributing to the detrimental prognosis of this disease. The immunohistochemical expression of the p53 tumor suppressor protein has been reported in 24% to 65% of feline oral squamous cell carcinomas, but no study has systematically evaluated in this tumor the presence of p53 encoding gene (TP53) mutations. The aim of this retrospective study was to determine whether p53 immunohistochemistry accurately reflects the mutational status of the TP53 gene in feline oral squamous cell carcinoma. Additionally, the prevalence of p53 dysregulation in feline oral squamous cell carcinoma was compared with that of feline non-neoplastic oral mucosa, in order to investigate the relevance of these dysregulations in cancer development. The association between p53 dysregulations and exposure to environmental tobacco smoke and tumor characteristics was further assessed. Twenty-six incisional biopsies of oral squamous cell carcinomas and 10 cases each of lingual eosinophilic granuloma, chronic gingivostomatitis and normal oral mucosa were included in the study. Eighteen squamous cell carcinomas (69%) expressed p53 and 18 had mutations in exons 5\u20138 of TP53. The agreement between immunohistochemistry and mutation analysis was 77%. None of non-neoplastic oral mucosa samples had a positive immunohistochemical staining, while one case each of eosinophilic granuloma and chronic gingivostomatitis harbored TP53 mutations. Unlike previously hypothesized, p53 dysregulations were not associated with exposure to environmental tobacco smoke. These results suggest an important role of p53 in feline oral tumorigenesis. Additionally, the immunohistochemical detection of p53 expression appears to reflect the presence of TP53 mutations in the majority of cases. It remains to be determined if the screening for p53 dysregulations, alone or in association with other markers, can eventually contribute to the early detection of this devastating disease

Longitudinal lymph node step-sectioning for the identification of metastatic disease in canine mast cell tumor

Lymph node (LN) metastasis in canine mast cell tumor (MCT) can affect prognosis and postsurgical treatment recommendations; however, routine histological single-section examination may underestimate the incidence of metastases. This prospective study aimed at determining whether longitudinal step-sectioning of the entire LN allows for a more reliable detection of metastases. Dogs with MCT undergoing resection of the primary tumor and regional lymphadenectomy were enrolled. Formalin-fixed LNs were bisected longitudinally, both halves were embedded in paraffin and histological sections prepared at 200 mu m steps. The nodal mast cells were classified according to the Weishaar classification. First-section evaluation (FSE; ie, examination of the first section obtained from the blocks) and whole LN step-section evaluation (SSE) were compared. Fifty-eight LNs were included. The median number of sections per LN was 6 (range, 3-28). FSE with toluidine blue (TB) revealed 27 (47%) nonmetastatic (HN0), 14 (24%) premetastatic (HN1), 9 (15%) early metastatic (HN2), and 8 (14%) overtly metastatic (HN3) LNs. SSE with TB resulted in upgrading the LN status in 2 cases (HN2 to HN3; HN0 to HN1). Evaluation of the first section plus an additional step-section resulted in 100% accuracy. Compared with SSE with TB, the accuracy of FSE with HE was 98% for HN3 LNs and 74% for HN2 LNs. FSE appears to reliably allow for the detection of LN metastasis in MCT, although examination of a further parallel section at a 200 mu m step may increase the accuracy. A metachromatic stain is recommended for the identification of early metastases

Expression profile of twelve transcripts as a supporting tool for the molecular characterization of canine cutaneous mast cell tumors at diagnosis: association with histological grading and clinical staging

Background/Objectives: Mast cell tumors (MCTs) are the second most common malignant neoplasms in dogs. Histopathological grading and clinical staging are the main tools for estimating biological behavior and disease extent; thus, both are essential for therapeutic decision-making and prognostication. However, the biological behavior of MCTs in dogs is variable, and it sometimes deviates from expectations. In a previous study, we identified 12 transcripts whose expression profile allowed a clear distinction between Kiupel low-grade and high-grade cutaneous MCTs (cMCTs) and was associated with prognosis. Building on these findings, this study evaluated the predictive potential of these transcripts’ expression profiles in classifying cMCTs into low-grade and high- grade. Methods: A logistic regression classifier based on the expression profiles of the identified transcripts and able to classify cMCTs as low- or high-grade was developed and subsequently tested on a novel dataset of 50 cMCTs whose expression profiles have been determined in this study through qPCR. Results: The developed logistic regression classifier reaches an accuracy of 67% and an area under the receiver operating characteristic curve (AUC) of 0.76. Interestingly, the molecular classification clearly identifies stage-IV disease (90% true positive rate). Conclusions: qPCR analysis of these biomarkers combined with the machine learning-based classifier might serve as a tool to support cMCT clinical management at diagnosis